Altersolanols

The catalytic effect of boron triacetate was used in a stereocontrolled synthesis of altersolanol B (6). ... 

Altersolanols A, B, C, D, E and F were extracted from Alternaria solani and baseline resolved on a 25°C Cjg column (A = 270 nm) using a complex 23-min 18/82- 90/10 acetonitrile/water gradient [1107]. Excellent peak shapes were generated. Detection limits of0.2-0.5pmol/5 pL injection (S/N = 3) were reported. A limited linear working range of 0.4—1.0 pM was also reported. 

This methodology has been exploited in the synthesis of a number of tri-and tetra-cyclic systems related to the fungal metabolite altersolanol Aand the anthracyclinone 3-rhodomycinone. As expected, cycloaddition occurred from the (3 face of the dieneophile providing a stereospecific, if low yielding, route to these systems [155] (Scheme 73). 

C-enriched. Small amounts of altersolanol B (65) and (66) were also isolated. Thus, it is claimed that altersolanol A is metabolised by A. solani to altersolanol B and macrosporin A. However, the mechanisms are somewhat difficult to visualise. 

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